But the point is Kia won’t guarantee in 3 or 4 years that Carplay will still work with their vehicles, and with significant interior refreshes occuring every 3-4 years, and if you’re Audi/BMW/Merc every 2 years, and iOS has major revisions every 1.5-2 years, and minor updates every few weeks, that’s a huge number of variables. The problem isn’t will it work now, but will it work when Apple next updates Carplay/iOS.
Carplay would not be easier to keep working. BMW has no control over Carplay and the more advanced functionality (such as wireless Carplay) they develop the more they have to test, maintain, bugfix, etc each and every time Apple decide to update iOS which is every month. The problem is that BMW (and any other manufacturer using Carplay) will have to continue developing their own software, while also making sure Carplay works. A good example of the extra work involved was last year when Apple made changes to iOS which broke some of the bluetooth controls for older BMW vehicles (https://www.cnet.com/roadshow/news/why-did-my-phone-stop-working-with-my-bmw/).
Compare that to iDrive which BMW controls 100%, it decides what development to carry out, when to do it, which vehicles to support, which peripherals to support, etc.
I worked for a company that was developing a new iOS App for a major newspaper a few years ago. After several months work Apple released an iOS update that meant the App was effectively handicapped. We had no control and it was a massive waste of time and money, but Apple have that control.
How can any company estimate supporting something for several years when they have so little control and thus no way to estimate cost of support?